减压阀能用于液体的减压。
参考答案：错
22. Was it _____the conference of APEC that made Shanghai the focus of the world then?
A．holding
B．to hold
C．held
D．having held
酸轧中间辊辊径的使用范围（）
A.520~460mm
B.550~450mm
C.480~390mm
D.580~470mm
